How Did We Invent Long Distance Calling?

May 2, 2015

Did long distance calling change the world? Certainly. Imagine keeping up with friends and family outside of your city by snail mail! Remember that distance calls have existed for far longer than electronic mail? people still like to hear each others' voices for clearcut communication that e-mail doesn't always provide. How did it start?

Several parties developed some form of long distance technology in the late 19th century, although the first call is believed to have been made in 1876. Do keep in mind that communication between two cities effectively qualified as a "distance" call at the time! An engineer invented a loading coil that strongly mitigated the attenuation of telephone signals in 1899, but that connected Denver to New York in 1911.

Stretching halfway across the continent was impressive, but the inventors of the day wanted to make calls all the way across North America. Using the coil technology also proved to be quite expensive, rendering it commercially unfeasible. Average-income families couldn't use the technology as we do today.

The "triode vacuum tube" underpinned the first transcontinental calling systems, and the year 1907 saw its invention. It underwent a trial-and-error period before engineers came to understand it more completely. That process passed quickly enough to place the first transcontinental call between New York and San Francisco in 1915. The technology became ubiquitous throughout the 1920s.

Every new technology has entered the market as an expensive luxury item or service, so the average-income family still hadn't begun to adopt long distance calls until well after the Second World War.

With transcontinental calling covered, if not perfected, telecommunications companies searched for a way to reliably link calls between continents. Most of us take intercontinental calls for granted. Did you know that these companies laid down huge cables along the ocean floor to accomplish it?

They began to use cables capable of "frequency multiplexing," which alternated the electrical signals carrying vocal recordings across several frequencies. In English, it allowed more calls to travel through a single cable at any given time. One cable could house up to 36 calls at once by the mid-1950s! The world's population sat at almost one-third of today's population, so 36 calls per cable didn't seem so unreasonable.

Microwave signals replaced the coaxial cables and vacuum tubes so prominent in the mid-twentieth century. Microwave signals actually saw the most use in local use because the receptor towers could send the signal anywhere quickly in the local vicinity at incredibly high volumes. Optical cables tend to carry distance calls now because they can transmit incredibly high amounts of digital information practically at light speed. We can look at those developments another day.

This raises some questions about the world filled with people making these calls! How have families stayed together thanks to long distance calling? How much stronger are friendships now that they can stay in touch? How much more efficient has business communication become since 1915?

Our favourite question of all is this: how did they lay the cables along the ocean floor? Get in touch with us to start a conversation today!